A high-resolution transmission electron microscopy study of interfaces between the {gamma}, B2, and {alpha}{sub 2} phases in a Ti-Al-Mo alloy
- Univ. of Wisconsin, Madison, WI (United States). Dept. of Materials Science and Engineering
- Univ. of Virginia, Charlottesville, VA (United States). Dept. of Materials Science and Engineering
Conventional and high-resolution transmission electron microscopy (HRTEM) were used to examine the interfacial structures in a Ti-50Al-5Mo alloy which was processed to produce combinations of {gamma}, B2, and {alpha}{sub 2} phases in a single sample. A small amount of a fourth phase labeled {zeta} was also found in the microstructure. It may be the phase Ti{sub 2}AlN, but confirmation requires analysis of the N content in the phase. In this alloy, the orientation relationship between the {gamma} and B2 phases is {l_brace}111{r_brace}{sub {gamma}}{parallel}{l_brace}110{r_brace}{sub B2} and [<10{bar 1}]{sub {gamma}}>{parallel}<111>{sub B2} with a coherent habit-plane interface parallel to ({l_brace}474){sub {gamma}}. The orientation relationship between the B2 and {alpha}{sub 2} (and also the {zeta}) phases is {l_brace}110{r_brace}{sub B2}{parallel}(0001){sub {alpha}{sub 2}/{zeta}} and <111>{sub B2}{parallel}<11{bar 2}0>{sub {alpha}{sub 2}/{zeta}} with a coherent interface parallel to the close-packed planes and along other orientations. The orientation relationship between the {alpha}{sub 2} (and also the {zeta}) and {gamma} phases is (0001){sub {alpha}{sub 2}/{zeta}}{parallel}{l_brace}111{r_brace}{sub {gamma}} and <11{bar 2}0>{sub {alpha}{sub 2}/{zeta}}{parallel}[<10{bar 1}]{sub {gamma}}>. The {alpha}{sub 2} phase has a coherent interface parallel to the close-packed planes, while the {zeta} phase appears to adopt the ({l_brace}474){sub {gamma}} interface plane of the {gamma}phase, similar to the B2 phase. The phase labeled {zeta} in this study has the same orientation relationship with the {gamma} and B2 phases as {alpha}{sub 2} but consists of an ABABAC... stacking of close-packed basal planes. The ({l_brace}474){sub {gamma}} habit plane interface between the {gamma} and B2 phases is analyzed by several different theories of interfacial structure, and microstructural evolution in this system is also discussed.
- OSTI ID:
- 264080
- Report Number(s):
- CONF-941016-; ISSN 0360-2133; TRN: 96:016472
- Journal Information:
- Metallurgical Transactions, A, Vol. 27, Issue 6; Conference: Materials week `94, Rosemont, IL (United States), 3-7 Oct 1994; Other Information: PBD: Jun 1996
- Country of Publication:
- United States
- Language:
- English
Similar Records
Structure and mechanical properties of copper/niobium multilayers
Orientation relationship, plasticity, twin relationship, and interfacial structure of the ???' isothermal martensitic transformation in Pu-Ga alloys